System for controlling hydraulic pressure and flow rate of oil in engine and control method thereof

ABSTRACT

A system for controlling hydraulic pressure and flow rate of oil in an engine, may include a first solenoid valve disposed in a channel connecting an inlet and an outlet of an oil pump supplying oil from an oil pan to the engine, and an electronic controller controlling the first solenoid valve on the basis of number of revolution of the engine, load of the engine, and temperature of the oil.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority to Korean Patent Application Number 10-2010-0084694 filed Aug. 31, 2010, the entire contents of which application is incorporated herein for all purposes by this reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a system for controlling hydraulic pressure and flow rate of oil in an engine and a control method thereof, and more particularly, to a system for controlling hydraulic pressure and flow rate of oil in an engine that can prevent frictional loss due to hydraulic pressure and unnecessary consumption of oil, by controlling the opening of a solenoid valve mounted in each channel in accordance with the speed and load of the engine and temperature of the oil to supply oil corresponding to the minimum flow rate required by each gallery, and a control method thereof.

2. Description of Related Art

In general, in vehicles, fuel and air flow into the combustion chamber of the engine and then are compressed and exploded, such that the pistons in the engine reciprocates up/down and the up-down reciprocation of the pistons is converted into rotation of the crankshaft, thereby achieving torque.

The parts in the engine make friction therebetween when generating power and the friction of the parts may reduce the power and decrease the life span of the engine.

Further, heat is generated with combustion in the combustion chambers by the pistons in the engine and the inside of the engine is cooled by supplying oil into the engine. The oil pump that supplies the oil into the engine operates in proportion to the operational speed of the engine. The oil discharged from the oil pump is supplied to the main and head gallery of the engine through an oil cooler for cooling and an oil filter for filtering.

However, the oil pressure is different at the oil pump and at the main and head gallery due to hydraulic pressure loss generated through the oil cooler or the oil filter or flow restrictors. The oil pressure should be set high at the oil pump in order to achieve the desired oil pressure at the main and head gallery.

Therefore, it is required to increase very high oil pressure at the oil pump to supply hydraulic pressure corresponding to the desired hydraulic pressure at each gallery, and accordingly, friction increases at the oil pump. According to the engine operating condition, the required oil flow at the branched oil consumption parts are varied. However, the oil flow delivered to those is mostly proportional to the engine speed at the engine. This makes excessive oil should be delivered at the normal engine operating condition in order to meet the minimum required oil flow at all the branched parts. This means oil pumping work should be high and hydraulic pressure loss increase at the oil pump, the oil cooler, and the oil filter and oil consumption is increased by unnecessarily supplying the oil.

The information disclosed in this Background of the Invention section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.

BRIEF SUMMARY OF THE INVENTION

Various aspects of the present invention are directed to provide a system for controlling hydraulic pressure and flow rate of oil in an engine that can prevent frictional loss due to hydraulic pressure and unnecessary consumption of oil, by controlling the opening of a solenoid valve mounted in each channel in accordance with the speed and load of the engine and temperature of the oil to supply oil corresponding to the minimum flow rate required by each gallery, and a control method thereof.

In an aspect of the present invention, the system for controlling hydraulic pressure and flow rate of oil in an engine, may include a first solenoid valve disposed in a channel connecting an inlet and an outlet of an oil pump supplying oil from an oil pan to the engine, and an electronic controller controlling the first solenoid valve on the basis of number of revolution of the engine, load of the engine, and temperature of the oil.

The system for controlling hydraulic pressure and flow rate of oil in the engine may further include a second solenoid valve disposed in a channel connecting an inlet and an outlet of an oil cooler connected to the oil pump so as to cool the oil at the outlet of the oil pump, and controlled to operate by the electronic controller.

The system for controlling hydraulic pressure and flow rate of oil in the engine may further may include a third solenoid valve disposed in a channel connecting the oil pump to a piston cooling gallery supplying the oil discharged through the outlet of the oil pump to a piston cooling jet disposed to distribute the oil to pistons, and controlled by the electronic controller to control flow rate of the oil to the piston cooling gallery.

The system for controlling hydraulic pressure and flow rate of oil in the engine may further include a fourth solenoid valve disposed in a channel connecting the oil pump to a head oil gallery supplying the oil discharged through the outlet of the oil pump to a cylinder head, and controlled by the electronic controller to control flow rate of the oil supplied to the head oil gallery.

In another aspect of the present invention, the system for controlling hydraulic pressure and flow rate of oil in an engine, may include a first solenoid valve disposed in a channel connecting an inlet and an outlet of an oil pump supplying oil from an oil pan to the engine, a second solenoid valve disposed in a channel connecting an inlet and an outlet of an oil cooler connected with the outlet of the oil pump and cooling the oil discharged from the oil pump, a third solenoid valve disposed in a channel formed between an oil filter and a piston cooling gallery supplying the oil to piston cooling jets such that the oil may be distributed to pistons, and controlling flow rate of the oil to the piston cooling gallery, a fourth solenoid valve disposed in a channel formed between the oil filter and a head oil gallery supplying the oil filtered through the oil filter connected with the oil cooler to a cylinder head, and controlling flow rate of the oil supplied to the head oil gallery, and an electronic controller controlling the first solenoid valve, the second solenoid valve, the third solenoid valve, and the fourth solenoid valve, on the basis of engine parameters including number of revolution of the engine, load of the engine, and temperature of the oil, wherein the electronic controller controls the first solenoid valve to control the oil supplied to a main oil gallery of the engine, in accordance with operations of the second solenoid valve, the third solenoid valve, and the fourth solenoid valve.

In further another aspect of the present invention, the method of controlling a system for controlling hydraulic pressure and flow rate of oil in an engine may include the steps of sensing engine parameters including number of revolution of the engine, load of the engine, and oil temperature by using sensors in a vehicle, controlling a second solenoid valve that controls flow rate supplied to an oil cooler connected to an oil pump when the sensed engine parameters may be lower or higher than reference values of the engine parameters, controlling a third solenoid valve that controls flow rate supplied to a piston cooling gallery from the oil pump when the sensed engine parameters may be lower or higher than reference values of the engine parameters, controlling a fourth solenoid valve that controls flow rate supplied to a head gallery from the oil pump on the basis of the sensed parameters, and controlling a first solenoid valve that controls flow rate supplied to a main gallery from the oil pump on the basis of operational states of the second solenoid valve, the third solenoid valve, and the fourth solenoid valve, and the sensed parameters, wherein one of the sensed engine parameters in controlling the second solenoid valve may be oil temperature.

A system for controlling hydraulic pressure and flow rate of oil in an engine and a control method thereof according to the present invention make it possible to prevent frictional loss due to hydraulic pressure and unnecessary consumption of oil, by controlling the opening of a solenoid valve mounted in each channel in accordance with the speed and load of the engine and temperature of the oil to supply oil corresponding to the minimum flow rate required by each gallery.

The methods and apparatuses of the present invention have other features and advantages which will be apparent from or are set forth in more detail in the accompanying drawings, which are incorporated herein, and the following Detailed Description of the Invention, which together serve to explain certain principles of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram illustrating a system for controlling hydraulic pressure and flow rate of oil in an engine according to an exemplary embodiment of the present invention.

FIG. 2 is a flowchart illustrating a control method of the system for controlling hydraulic pressure and flow rate of oil in an engine shown in FIG. 1.

It should be understood that the appended drawings are not necessarily to scale, presenting a somewhat simplified representation of various features illustrative of the basic principles of the invention. The specific design features of the present invention as disclosed herein, including, for example, specific dimensions, orientations, locations, and shapes will be determined in part by the particular intended application and use environment.

In the figures, reference numbers refer to the same or equivalent parts of the present invention throughout the several figures of the drawing.

DETAILED DESCRIPTION OF THE INVENTION

Reference will now be made in detail to various embodiments of the present invention(s), examples of which are illustrated in the accompanying drawings and described below. While the invention(s) will be described in conjunction with exemplary embodiments, it will be understood that present description is not intended to limit the invention(s) to those exemplary embodiments. On the contrary, the invention(s) is/are intended to cover not only the exemplary embodiments, but also various alternatives, modifications, equivalents and other embodiments, which may be included within the spirit and scope of the invention as defined by the appended claims.

Referring to FIG. 1, in a system for supplying oil into the engine, as the engine starts, an oil pump 12 pumps up oil from an oil pan 11 connected with the inlet and discharges the oil through the outlet. The oil is sent under predetermined pressure to an oil cooler 13 connected with the outlet of oil pump 12 and cooled through oil cooler 13. The oil cooled through oil cooler 13 is filtered through an oil filter 14 and supplied to a main oil gallery 16 in the cylinder block of the engine.

The oil supplied to main oil gallery 16 is supplied to each main bearing journals of the cylinder block.

The oil filtered through oil filter 14 is supplied to a head oil gallery 15 in the cylinder head of the engine. The oil supplied to head oil gallery 15 is supplied to the locker shaft of the cylinder head and into the cylinder head.

The oil filtered through oil filter 14 is supplied to a piston cooling gallery 17 in the cylinder block of the engine. The oil supplied to piston cooling gallery 17 is supplied to each piston through a plurality of piston cooling jet 18.

A system 100 for controlling hydraulic pressure and flow rate of oil in an engine includes a first solenoid valve Vs1 in the channel connecting the inlet with the outlet of oil pump 12, such that it can prevent hydraulic pressure from excessively increasing at the outlet of oil pump 12 by controlling the opening of the channel between the inlet and the outlet of oil pump 12, in accordance with the oil temperature and the vehicle speed. First solenoid valve Vs1 is electrically connected with an electronic controller 110 and controlled to operate by the electronic controller 110.

Oil pump 12 operates in proportion to the engine speed, and even if oil pump 12 operates at the same speed, the hydraulic pressure is high when the oil temperature is low and the hydraulic pressure is relatively low when the oil temperature is high, as compared with when the oil temperature is low.

Therefore, electronic controller 110 controls first solenoid valve Vs1 such that the hydraulic pressure from oil pump 12 is controlled in accordance with the oil temperature and the vehicle speed, in order to prevent the pressure of the oil discharged from oil pump 12, which operates in proportion to the engine speed, from increasing when the oil temperature is low.

That is, electronic controller 110 controls first solenoid valve Vs1 such that desired hydraulic pressure required for main oil gallery 16 is supplied, in accordance with the engine speed and the engine load in the cold period where the oil temperature is low.

Further, system 100 for controlling hydraulic pressure and flow rate of oil in an engine further includes a second solenoid valve Vs2 between the inlet and the outlet of oil cooler 13. That is, second solenoid valve Vs2 controls flow rate in the channel connecting the outlet of oil pump 12 and the inlet of oil filter 14.

Second solenoid valve Vs2 is controlled to open the channel between the inlet and the outlet of oil cooler 13 by electronic controller 110 in accordance with the oil temperature such that the oil discharged from oil pump 12 is directly supplied to oil filter 14, without being cooled through oil cooler 13.

As described above, electronic controller 110 can prevent pressure loss through oil cooler 13 by opening second solenoid valve Vs2 such that the oil discharged from oil pump 12 is directly supplied to oil filter 14, without operating oil cooler 13, when the oil temperature is low.

Further, system 100 for controlling hydraulic pressure and flow rate of oil in an engine further includes a third solenoid valve Vs3 between the outlet of oil filter 14 and piston cooling gallery 17.

Third solenoid valve Vs3 controls the amount of oil supplied to piston cooling gallery 17 on the basis of the number of revolution of engine, the engine load, and the oil temperature.

Third solenoid valve Vs3 controls unnecessary excessive supply of oil to a piston cooling jet 18, while the vehicle travels at a low speed, on the basis of the number of revolution of engine, the engine load, and the oil temperature. The engine load may be determined from the position of the driving gear of the vehicle, the amount of fuel, and the temperature of cooling water.

Electronic controller 110 can prevent oil supply to piston cooling gallery 17 by closing third solenoid valve Vs3 while the vehicle travels at a low speed under a predetermined speed.

Since the larger the flow rate of the oil supplied to piston cooling gallery 17 through third solenoid valve Vs3, the more the hydraulic pressure decreases at the outlet of oil pump 12, under the same engine speed and the same oil temperature, electronic controller 110 controls the hydraulic pressure at the outlet of oil pump 12 by operating third solenoid valve Vs3 in accordance with the vehicle speed and the oil temperature.

Further, system 100 for controlling hydraulic pressure and flow rate of oil in an engine further includes a fourth solenoid valve Vs4 between the outlet of oil filter 14 and head oil gallery 15.

Fourth solenoid valve Vs4 controls the amount of oil supplied to head oil gallery 15 on the basis of the revolution number of engine, the engine load, and the oil temperature.

The opening of fourth solenoid valve Vs4 is controlled by electronic controller 110 on the basis of the number of revolution of engine, the engine load, and the oil temperature, to supply the minimum amount of oil required for head oil gallery 15. The engine load may be determined from the position of the driving gear of the vehicle, the amount of fuel, and the temperature of cooling water.

Further, the smaller the opening of fourth solenoid valve Vs4, the more the hydraulic pressure applied to main oil gallery 16 decreases. Further, with second solenoid valve Vs2 open, the hydraulic pressure applied to main oil gallery 16 decreases, while the smaller the opening of third solenoid valve Vs3, the more the hydraulic pressure applied to main oil gallery 16 decreases.

Therefore, electronic controller 110 controls the opening of first solenoid valve Vs1 to prevent the flow rate to main oil gallery 16 from decreasing, in accordance with the opening of second solenoid valve Vs2, third solenoid valve Vs3, and fourth solenoid valve Vs4, thereby re-compensating the flow rate from oil pump 12 to the desired flow rate.

Although all of first solenoid valve Vs1, second solenoid valve Vs2, third solenoid valve Vs3, and fourth solenoid valve Vs4 of system 100 for controlling hydraulic pressure and flow rate of oil in an engine is shown in FIG. 1, at least only any one of solenoid valves Vs1, Vs2, Vs3, and Vs4 may be included, for the features of the engine of the vehicle.

As described above, since first solenoid valve Vs1, second solenoid valve Vs2, third solenoid valve Vs3, and fourth solenoid valve Vs4 are controlled by electronic controller 110 in accordance with the engine speed, the engine load, and the oil temperature, in system 100 for controlling hydraulic pressure and flow rate of oil in an engine, it is possible to supply flow rate corresponding to the desired minimum flow rate required for each gallery. Therefore, it is possible to reduce frictional pressure applied to the oil pump and improve fuel efficiency by preventing unnecessarily excessive flow rate and frictional loss due to the increase of hydraulic pressure.

On the other hand, a method of controlling system 100 for controlling hydraulic pressure and flow rate of oil in an engine show in FIG. 1 includes measuring parameters (S1), controlling second solenoid valve (S2), controlling third solenoid valve (S3), controlling fourth solenoid valve (S4), and controlling first solenoid valve (S5), as shown in FIG. 2. The method of controlling system 100 for controlling hydraulic pressure and flow rate of oil in an engine is described with reference to system 100 for controlling hydraulic pressure and flow rate of oil in an engine shown in FIG. 1.

Sensing parameters transmitting parameters measured by sensors of the vehicle to electronic controller 110 (S1) is first performed to measure the number of revolution of engine, the engine load, and the oil temperature. The engine load may be determined from the position of the driving gear of the vehicle, the amount of fuel, and the temperature of cooling water.

Electronic controller 110 performs the controlling of solenoid valves for controlling solenoid valves Vs1, Vs2, Vs3, and Vs4 (S2, S3, S4, and S5) after comparing the transmitted parameter values Pa with reference values.

Electronic controller 110 determines whether the sensed oil temperature To is smaller than a reference temperature A to perform the controlling of second solenoid valve (S2) (S21). Electronic controller 110 closes second solenoid valve Vs2 (S23) to supply the oil cooled through oil cooler 13 to oil filter 14, when determining that the oil temperature To is higher than the reference temperature A.

Electronic controller 110 can prevent the pressure from being reduced by oil cooler 13 by opening second solenoid valve Vs2 (S22) such that the oil bypasses, without operating oil cooler 13, when the oil temperature To is smaller than the reference temperature A. Electronic controller 110 controls the flow rate to main oil gallery 16 by controlling second solenoid valve Vs2 on the basis of the amount of opening estimated from parameter values 19.

Further, electronic controller 110 compares the parameter values Pa transmitted to perform the controlling of third solenoid valve (S3) with reference values Th (S31).

For example, electronic controller 110 determines that the vehicle is traveling at a low speed, and prevents the oil supply to piston cooling gallery 17 by closing third solenoid valve Vs3 (S32), when the number of revolution of engine in the parameter values Pa is less than the reference number of revolution Th.

Electronic controller 110 controls the amount of opening of third solenoid valve such that the desired flow rate required by piston cooling gallery 17 in accordance with the number of revolution of engine, the engine load, and the oil temperature is supplied, when the parameter values Pa are larger than the reference values.

Electronic controller 110 controls the amount of opening of fourth solenoid valve Vs4 (S4) to supply the desired flow rate required for head oil gallery 15 in accordance with the number of revolution of engine, the engine load, and the oil temperature, which are the parameter values Pa, in order to perform the controlling of fourth solenoid valve.

Electronic controller 110 calculates the amount of opening of first solenoid valve Vs1 for supplying the desired flow rate required for main oil gallery 16 (S51), in accordance with the operational states of second solenoid valve Vs2, third solenoid valve Vs3, and fourth solenoid valve Vs4, and the number of revolution of engine, the engine load, and the oil temperature, which are the parameter values Pa, in order to perform the controlling of fifth solenoid valve (S5). Further, electronic controller 110 controls first solenoid valve Vs1 to be opened as much as the calculated amount of opening of first solenoid valve Vs1 (S52).

As described above, since first solenoid valve Vs1, second solenoid valve Vs2, third solenoid valve Vs3, and fourth solenoid valve Vs4 are controlled by electronic controller 110 in accordance with the engine speed, the engine load, and the oil temperature, in the method of controlling system 100 for controlling hydraulic pressure and flow rate of oil in an engine, it is possible to supply flow rate corresponding to the desired minimum flow rate required for each gallery. Therefore, it is possible to reduce frictional pressure applied to the oil pump and improve fuel efficiency by preventing unnecessarily excessive flow rate and frictional loss due to the increase of hydraulic pressure.

The above description is an embodiment for implementing a system for controlling hydraulic pressure and flow rate of oil in an engine and a control method thereof of the present invention and the present invention is not limited thereto. Accordingly, the present invention may be modified in various ways by those skilled in the art without departing from the scope of the present invention, which is described in the following claims, and the modifications should be construed as being included in the present invention. 

What is claimed is:
 1. A system for controlling hydraulic pressure and flow rate of oil in an engine, comprising: a first solenoid valve disposed in a channel connecting an inlet and an outlet of an oil pump supplying oil from an oil pan to the engine; and an electronic controller controlling the first solenoid valve on the basis of number of revolution of the engine, load of the engine, and temperature of the oil.
 2. The system for controlling hydraulic pressure and flow rate of oil in the engine as defined in claim 1, further comprising a second solenoid valve disposed in a channel connecting an inlet and an outlet of an oil cooler connected to the oil pump so as to cool the oil at the outlet of the oil pump, and controlled to operate by the electronic controller.
 3. The system for controlling hydraulic pressure and flow rate of oil in the engine as defined in claim 1, further comprising a third solenoid valve disposed in a channel connecting the oil pump to a piston cooling gallery supplying the oil discharged through the outlet of the oil pump to a piston cooling jet disposed to distribute the oil to pistons, and controlled by the electronic controller to control flow rate of the oil to the piston cooling gallery.
 4. The system for controlling hydraulic pressure and flow rate of oil in the engine as defined in claim 1, further comprising a fourth solenoid valve disposed in a channel connecting the oil pump to a head oil gallery supplying the oil discharged through the outlet of the oil pump to a cylinder head, and controlled by the electronic controller to control flow rate of the oil supplied to the head oil gallery.
 5. A system for controlling hydraulic pressure and flow rate of oil in an engine, comprising: a first solenoid valve disposed in a channel connecting an inlet and an outlet of an oil pump supplying oil from an oil pan to the engine; a second solenoid valve disposed in a channel connecting an inlet and an outlet of an oil cooler connected with the outlet of the oil pump and cooling the oil discharged from the oil pump; a third solenoid valve disposed in a channel formed between an oil filter and a piston cooling gallery supplying the oil to piston cooling jets such that the oil is distributed to pistons, and controlling flow rate of the oil to the piston cooling gallery; a fourth solenoid valve disposed in a channel formed between the oil filter and a head oil gallery supplying the oil filtered through the oil filter connected with the oil cooler to a cylinder head, and controlling flow rate of the oil supplied to the head oil gallery; and an electronic controller controlling the first solenoid valve, the second solenoid valve, the third solenoid valve, and the fourth solenoid valve, on the basis of engine parameters including number of revolution of the engine, load of the engine, and temperature of the oil.
 6. The system for controlling hydraulic pressure and flow rate of oil in the engine as defined in claim 1, wherein the electronic controller controls the first solenoid valve to control the oil supplied to a main oil gallery of the engine, in accordance with operations of the second solenoid valve, the third solenoid valve, and the fourth solenoid valve.
 7. A method of controlling a system for controlling hydraulic pressure and flow rate of oil in an engine, comprising the steps of: sensing engine parameters including number of revolution of the engine, load of the engine, and oil temperature by using sensors in a vehicle; controlling a second solenoid valve that controls flow rate supplied to an oil cooler connected to an oil pump when the sensed engine parameters are lower or higher than reference values of the engine parameters; controlling a third solenoid valve that controls flow rate supplied to a piston cooling gallery from the oil pump when the sensed engine parameters are lower or higher than reference values of the engine parameters; controlling a fourth solenoid valve that controls flow rate supplied to a head gallery from the oil pump on the basis of the sensed parameters; and controlling a first solenoid valve that controls flow rate supplied to a main gallery from the oil pump on the basis of operational states of the second solenoid valve, the third solenoid valve, and the fourth solenoid valve, and the sensed parameters.
 8. The method of controlling a system for controlling hydraulic pressure and flow rate of oil in an engine as defined in claim 1, wherein one of the sensed engine parameters in controlling the second solenoid valve is oil temperature. 